It is well known that when fluid is removed from a closed fluid container the pressure inside the container drops, which may result in collapse of the container. However, this does not happen in open systems because the pressure difference between the inside and outside of the container causes air to pass into the container and replace the fluid that has been removed. Conversely, as fluid is pumped into the container, air is forced out. The air that moves in and out of the container has many contaminants that may be harmful to the fluid inside the container, other objects in the vicinity of the container and also to the container itself As a result, the fluid inside the container can become contaminated over time and thus, will have to be changed, resulting in economic loss.
For example, water vapor that is associated with the air can cause rust and oxidation of the container, which will result in deterioration of the fluid, as well as damage to the container, which then will have to be changed periodically. Moreover, solid particles in the air stick to the container causing wear and tear of the container. Additionally, the solid particles cause abrasive wear on components serviced by the fluid. For example, in hydraulic systems, the fluid flows through cylinders, or in a gear box where the fluid is in contact with gear surfaces, solid particles will cause wear on such parts. Furthermore, acids and salts in the air may react with the fluid or the container causing further degradation of the fluid and/or the container. This kind of chemical reaction may further result in corrosion, overheating and microbial growth.
On the other hand, air leaving such containers may be harmful to the environment. For example, as a battery is recharged, gas containing contaminants, like hydrogen and sulphuric acid gas are released into the atmosphere. Note that hydrogen gas is combustible and sulphuric acid gas is corrosive. Consequently, gas recharge areas are subject to strong regulation regarding health and safety. Moreover, open flames are often used in these work areas increasing the risk of explosions.
The filtering of air to remove dust particles and moisture before entering the fluid container has been illustrated in patents issued to Waller et al, U. S. Pat. Nos. 4,504,289 and 4,548,624 (hereinafter "Waller"). In systems, such as Waller, air enters through an aperture at the bottom of the breather cap (bottom being defined as the portion of the breather cap positioned nearest to the container) and passes upward through two particle filters and desiccant before being allowed to enter the top opening of a central standpipe. The filtered air flows downward through the standpipe into the container. Such systems do not provide for any filtration or cleaning of the air once the air enters the standpipe. Since the standpipe extends from the top to the bottom of the breather it may introduce contaminants into the air before the air enters the container. The longer the path that the air travels to enter the container after it has been filtered, the greater the likelihood of the air being contaminated when it enters the container. Moreover, air leaving the container and flowing backward up the standpipe will contain dust particles and other contaminants that will stick to the inside of the standpipe causing the incoming air to become contaminated. Thus, the air entering the container is not as clean as it should be.
Furthermore, the amount of desiccant used by such systems for a particular size breather is limited due to the presence of the central standpipe which occupies substantial space inside the breather. This reduces the adsorption capacity of the breather resulting in more frequent replacements of the desiccant and the breather. The breather and the desiccant being replaced more frequently results in increased contamination. Failure to change the desiccant and the filters at periodic intervals increases the likelihood that the desiccant and/or the filters will be contaminated and thus not effective. Furthermore, since air in existing systems enters the breather through an aperture at the bottom, it is more likely that outside condensation will also flow into the breather along with the air thereby increasing the water vapor inside the container.
Therefore, there is a need in the art for a system which solves these and other deficiencies of known systems, while providing a contamination control breather for fluid containers and other air displacement systems.
Another object of the present invention is to provide a contamination control breather in which air is forced to pass through a maximum amount of desiccant per unit volume before entering the container.
A further object of the present invention is to provide a contamination control breather in which air is forced to pass through a maximum amount of activated charcoal per unit volume before leaving the breather.
Still, a further object of the present invention is to provide a contamination control breather in which air passes directly to the container after passing through the filters, the activated charcoal and the desiccant.
Still a further object of the present invention is to provide a contamination control breather in which the two caps are the same size.
Still a further object of the present invention is to provide a contamination control breather with a color indicator to indicate when the maximum adsorption capacity of the desiccant has been reached.
Still a further object of the present invention is to provide a contamination control breather with anti-static filters to reduce the potential for explosion that exists in any dusty environment.
Still a further object of the present invention is to provide a contamination control breather with diffusers to ensure maximum effectiveness within the desiccant chamber.
Still a further object of the present invention is to provide a contamination control breather that forces the incoming air to pass through the filters and the desiccant.
Still a further object of the present invention is to provide a contamination control breather that forces the outgoing air to pass through filters, desiccant, charcoal and a flame retardant disc.
Still a further object of the present invention is to provide a contamination control breather with strong supports to connect the breather to containers that are highly agitated in their normal operation.
Still a further object of the present invention is to provide a contamination control breather for controlling the amount of air that goes in the breather.
Still a further object of the present invention is to provide a contamination control breather with a constant cross-section throughout its entire length.
Still a further object of the present invention is to provide a contamination control breather for neutralizing harmful contaminants present in gases or air, leaving the breather.